1. Field of the Invention
This invention relates generally to a method and apparatus for automatic self-testing of electrical devices, and more particularly to a method and apparatus for automatic self-testing of electrical defibrillators.
2. Description of the Prior Art
Sudden cardiac death is the leading cause of death in the United States. Most sudden cardiac death is caused by ventricular fibrillation, in which the heart's muscle fibers contract without coordination, thereby interrupting normal blood flow to the body. The only known effective treatment for ventricular fibrillation is electrical defibrillation, in which an electrical pulse is applied to the patient's heart. The electrical pulse must be delivered within a short time after onset of ventricular fibrillation in order for the patient to have any reasonable chance of survival.
External defibrillators send electrical pulses to the patient's heart through electrodes applied to the patient's torso. External defibrillators are typically located and used in hospital emergency rooms, operating rooms, and emergency medical vehicles. Of the wide variety of external defibrillators currently available, automatic and semi-automatic external defibrillators ("AEDs") are becoming increasingly popular because they can be used by relatively inexperienced personnel. Such defibrillators are also especially lightweight, compact, and portable.
AEDs provide a number of advantages, including the availability of external defibrillation at locations where external defibrillation is not regularly expected, such as in residences, public buildings, businesses, personal vehicles, public transportation vehicles, etc. AEDs are typically subject to widely varying conditions and are used relatively infrequently, but are nevertheless expected to function reliably when used. Thus, regular testing of an AED is desirable, in order to sample readiness for use should it be needed. However, operators trained in the use of AEDs are usually inexperienced in the testing of medical equipment. Therefore, testing of AED functions is preferably performed automatically by the AED itself (known in the art as "self-testing"). Conventional self-testing systems for defibrillators test at regularly scheduled time intervals and/or in response to certain events, such as power-on events. As such, conditions potentially affecting certain defibrillator functions may not be adequately detected, and defibrillator reliability may then be compromised.